How do I stream data to browsers with Hapi?

2020

I found it !! the problem was the gzip compression

to disable it just for event-stream you need provide the next config to Happi server

const server = Hapi.server({
  port: 3000, 
  ...
  mime:{
    override:{
      'text/event-stream':{
        compressible: false
      }
    }
  }
});

in the handler I use axios because it support the new stream 2 protocol

async function handler(req, h) {
    const response = await axios({
        url: `http://some/url`,
        headers: req.headers,
        responseType: 'stream'
    });

    return response.data.on('data',function (chunk) {
        console.log(chunk.toString());
    })

    /* Another option with h2o2, not fully checked */
    // return h.proxy({
    //     passThrough:true,
    //     localStatePassThrough:true,
    //     uri:`http://some/url`
    // });
};

Try using Readable.wrap:

var Readable = require('stream').Readable;
...
function (request, reply) {

  var s = Request('http://www.google.com');
  reply(new Readable().wrap(s));
}

Tested using Node 0.10.x and hapi 8.x.x. In my code example Request is the node-request module and request is the incoming hapi request object.

UPDATE

Another possible solution would be to listen for the 'response' event from Request and then reply with the http.IncomingMessage which is a proper read stream.

function (request, reply) {

     Request('http://www.google.com')
     .on('response', function (response) {
        reply(response);
     });
}

This requires fewer steps and also allows the developer to attach user defined properties to the stream before transmission. This can be useful in setting status codes other than 200.